The present invention relates generally to agricultural machinery and, more particularly, to a segmented sieve lining for a concave in a threshing mechanism of a harvesting machine.
In a combine harvester, a feed conveyor transports crops to be threshed to a threshing mechanism that includes a threshing cylinder and a concave. The width of the feed conveyor is normally less than the width of the threshing cylinder and concave. The feed conveyor extends into the housing of the threshing mechanism to ensure satisfactory transfer of crops. The threshing mechanism housing has an inspection opening located above the outlet end of the feed conveyor. The inspection opening serves, in part, to allow removal of a sieve lining on the concave of the threshing mechanism for maintenance work. European patent EP 0396 968 discloses a concave that is longitudinally divided, forming individual sieve lining sections which can be successively removed from the threshing mechanism housing through the inspection opening. The concave as a whole is mounted so as to be pivotable about a horizontal axis, and can be lowered by means of a linkage from the working position to a non-working position and pivoted back to the working position in the reverse manner.
To increase the output of a combine harvester it is necessary to increase the diameter of the threshing cylinder. This results in a need for a larger concave and sieve lining. A problem arises in that the larger sieve lining is then no longer removable through the inspection opening in the cramped space of the threshing mechanism housing.
The present invention includes an extension which increases the encompassment of the threshing cylinder by the sieve lining and which is connected with the sieve lining segments without a gap. The sieve lining segments themselves remain small enough to remove through the inspection opening in the threshing mechanism housing. There is an articulated connection between the extension and the sieve lining segments.
In one embodiment, the extension is a single piece. Alternatively, the extension is divided into a plurality of extension segments.
In another embodiment, the articulated connection is a permanent connection, such as a hinge. Another embodiment has a form-locking design in which an angled edge associated with the extension engages with a U-shaped edge associated with the sieve lining segments.
One object of the present invention is to provide a design for a segmented sieve lining such that removal of the sieve lining segments is possible while retaining the cramped spaces in a combine harvester with a threshing cylinder of larger diameter than previous designs.
Another object of the present invention is to provide a sieve lining that accommodates the required size of the concave for added output of the harvester while still allowing the lining segments to be removed from the threshing mechanism housing through the inspection opening.
In accordance with the present invention there is provided a combine harvester having front and rear ends and including a transversely-extending threshing mechanism and a threshing mechanism housing which has an inspection opening at the front thereof, the threshing mechanism including a transversely-extending threshing cylinder and a concave at the bottom of the threshing cylinder, the inspection opening having a width less than a length of the threshing cylinder, the concave including a plurality of sieve lining segments in a side-by-side arrangement generally across the length of the threshing cylinder, each sieve lining segment having a width in the transverse direction which is less than the width of the inspection opening while the total width of all of the abutting sieve lining segments is equal to the concave.
These and other objects, aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the reference drawings.